Air volume control mechanism



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AIR VOLUME CONTROL MECHANISM Filed Jan. 24, 1945 2 SI'lEETS-SHEET 2 F1 g-4- a? 8 V E 1'1 IE .I.

JZ'riL Patented Dec. 16, 1952 AIR VOLUME CONTROL MECHANISM Arthur W. Burks, Decatur, 111., assignor to Decatur Pump Company, Decatur, 111., a corporation of Illinois Application January 24, 1945, Serial No. 574,399

9 Claims. 1

This invention relates to an air volume control mechanism that is primarily adapted for incorporation in a hydro-pneumatic water supply system. Such a supply system is disclosed in my issued Patents Nos. 2,172,057 and 2,172,097, both dated September 5, 1939.

The mechanism of my present invention constitutes an improvement over the inventions of my prior issued patents in that it is simpler in construction and operation and not so likely to get out of order.

In accordance with my present invention, an air volume control mechanism of the diaphragm type is provided for connection to a hydropneumatic tank at approximately the normal water level thereof, and also for connection to the suction side of the pump supplying water to the hydro-pneumatic tank. Under the suction action of the pump, when the pump is operating, the diaphragms of the mechanism are held in such a position as to cause a charge of air to be drawn in through a check valve controlled inlet valve into the diaphragm casing. Means, such as a spring or a gravity acting weight, are provided for acting, when the pump shuts down, to move the diaphragms in the opposite direction and expel the charge of air back into the tank. Thus, upon every operation of starting and stopping the pump, air is drawn into the device while the pump is operating and is expelled from the device into the tank when the pump shuts down.

It is therefore an important object of this invention to provide a simple yet rugged device of improved construction and operation for association with a hydro-pneumatic tank and a water pump therefor to maintain the required air pressure within the tank, the device being responsive 'to the action of diaphragms upon the shutting down of the pump to expel air from the device back into the hydro-pneumatic tank.

It is a further important object of this invention to provide an air volume control mechanism for maintaining the desired pressure within a hydro-pneumatic tank that acts positively and promptly in response to tank pressure and pump suction to force a charge of air into the hydropneumatic tank if the air pressure in said tank is below that required.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

On the drawings: Figure 1 is a sectional view of an air volume control mechanism, with parts in elevation, illusitrating diagrammatically its connection to a.

hydro-pneumatic tank and to a pump for supplying water to said tank.

Figure 2 is a similar sectional view showing the diaphragm mechanism in the position of having just drawn air thereinto.

Figure 3 is a sectional view, with parts in elevation, of a modified form of my device, illustrating diagrammatically its association with a hydropneumatic tank and the pump for delivering water to said tank.

Figure 4 is a sectional view similar to that shown in Figure 3 but with the diaphragm mechanism in the position of having just drawn air thereinto.

The air volume control mechanism of my invention, as previously stated, is intended primarily for association with a hydro-pneumatic tank, indicated generally by the reference numeral 10 and with the pump 11, shown diagrammatically, that serves to supply said tank with water. As shown in Figures 1 and 2, my air volume control mechanism 12 comprises a two-part casing 13 having a threaded opening 14 for connection by means of a nipple 15 to said tank 10 at approximately the normal water level therein. Said normal water level is indicated by the dotted line K, and somewhat higher and lower water levels are indicated by the dotted lines J and L, respectively.

The two-part casing 13 comprises .a part 16 having one open side defined by an annular flange I1, and a second part 18 having an annular flange 19 for attachment to said flange 11 by means of screws 20. A relatively large flexible diaphragm 21, preferably formed of rubber, is clamped at its periphery between said flanges l1 and 19. A second, relatively smaller diaphragm 22 is positioned within the casing part I 6 with its periphery clamped between inner wall portions 23 of said casing part and the annular flange 24 of a conically shaped stop member 25. The diaphragms 21 and 22remain generally in parallelism during their movement, as will later. be explained. Said diaphragms divide theinterior of the casing 13 into outer chambers F and H and an intermediate chamber G.

The diaphragm 2! is centrally apertured with its inner circular margin 26 clamped between the flange 2'1 of a rigid cup-shaped member28 and an annular Washer 29, as by means of bolts and nuts 30. The cup-shaped portion of said member 28 extends through the opening 31 provided in the inwardly inclined walls of said stop member 25. The outer surface of the bottom with a coaxial pilot recess 33, into which extends a boss 34 formed centrally of the diaphragm 22. The interior wall of said bottom portion 32 is provided with a cylindrical boss 35 that serves to center one end of a coiled spring 36. The other end of said spring 36 is seated in a circular recess 31 formed in the inner wall of said casing portion I8. Said spring 36 is thus held under compression between said recess 3'! and the bottom wall 32 of the cup-shaped member 23. The spring 36 should be as light as possible and still be operative to perform its function, as will later be described.

The stop member 25, as illustrated in Figure 1, serves as a stop against further movement of the diaphragm 2| and cup-shaped member 22 toward the left, while when the movement or" the diaphragm 2| is toward the right, as viewed in Figure 2, the inclined wall of said stop member 25 serves as a support for said diaphragm 22. The stop member 25 is apertured at 38 to provide a communication between the main portion of the chamber G and the smaller chamber G formed when the diaphragms are in the position illustrated in Figure l.

The threaded intake I4 is formed with a coaxial extension 43 having a reduced threaded bore portion 4| and an offset assageway 42 leading therefrom to the chamber G. A check valve assembly 43 is inserted through said opening l4 and bore and threaded into the threaded reduced bore portion 4|. Said check valve assembly 43 includes a valve seat 44 at the entranc to the pasage 45 extending through the reduced end portion of the valve casing. A hollow ball 46 is positioned within the enlarged portion 41 of said check valve assembly and held against displacement therefrom by a cross pin 48.

With this construction of check valve assembly, air can pass in either direction therethrough, but water cannot pass from the tank I6 into the chamber G for the reason that the ball 46, being lighter than water, will promptly rise and seat in the valve seat 44 whenever water tends to fill the check valve assembly.

' A nipple 49 is screwed into an opening 50 in the top wall of the casing |3 and carries a pressure gauge (not shown) for registering the pressure inside said casing l3, and also, therefore, the pressure within said tank [6.

An air intake valve assembly, indicated generally by th reference numeral 5|, is positioned in the lower part of the casing portion I6 for admission of air into the chamber G. Said air intake assembly 5| includes a nipple 52 having a small passage 53 extending axially thereof. Said passage 53 is counterbored, as at 54,at its inner end for receiving a resilient valve seat 55. A ball 56 is mounted for seating upon said valve seat and for this purpose has a stem portion 51 extending through the bore 53 and projecting therebeyond. On the lower projecting end ofthe stem portion 5'! is an enlargement 58 forming a stop to prevent displacement of the ball and stem from the bore 53. As is apparent from the construction of the air intake valve assembly 5|, air can enter the chamber G through the bore 53 when the ball 56 is raised, as illustrated in Figure 2, but air cannot find its way out of chamber G through said check valve assembly due to the fact that the ball 56 seats against the seat 54 whenever the air pressure within the chamber G is greater than that surrounding the casing l3.

A connection is provided from the intake side, or suction side, of the pump H to the casing l3. This connection includes the piping 66 coupled to a nipple 6| that is threaded into the threaded portion 62 of a passage 63 in the lower portion of the casing part I8. Under the action of the pump, when operated, a drop in pressure takes place at the intake side of the pump and this drop in pressure is translated through the piping 60, nipple 6| and passag 63 to the chamber H.

The operation of the air control mechanism l2 as illustrated in Figures 1 and 2 will now be described in more detail.

Assume the level of the water in the tank It! to be that indicated by the dotted line J, with compressed air above this level and with the pump not in operation. At this point, the pressures in chambers F, G and H are equalized at tank pressure. The diaphragms 2| and 22 are then in the positions shown in Fig. 1. When the pump H is started up, the suction effect just referred to causes a partial vacuum to be formed in the chamber I-I. Since the spring 36 is weaker than the suction eifect set up by the pump, plustank pressure exerted against the diaphragm 22, its compression force will be overbalanced and the diaphragms 2| and 22 will tend to move in unison toward the right, as viewed in Figures 1 and 2, until movement is stopped by the screws 36 hitting up against the outer wall of the casing part i8. Such movement of the diaphragms 2| and 22 to the right increases the volume of the chamber G, due to the differences in the sizes of the diaphragms, with the result that air is drawn in through the air intake assembly 5|, through the bore 53 into the chamber G, the ball 56 being raised from its'seat, as illustrated in Figure 2, due to the drop in pressure inthe chamber G. During this stage of the operation, there is a tendency for the partial vacuum in the chamber G to draw. in water from the tank 10 through the check valve assembly 43. This is prevented be cause the ball 46 leaves the stop pin 48 against which it normally rests and, actuated by the moving water moves up against the valve seat 44, as illustrated in Figure 2, thereby preventing water from the tank In passing into the chamber G. At this point a full charge of air has been taken into the chamber G, the air valve 56 has dropped back into its seat and the pump I! is still running. Whenthe pump stops, the chambers F, G and H are equalized at tank pressure, the spring 36 exerts its compressive force to move the diaphragms 2| and 22 in unison to the left until they reach the extreme position illustrated in Figure 1. As the diaphragms move to this extreme position, the check valve ball 56 being seated, air is forced out of the chamber G due to said chamber being restricted in volume and is caused to pass through the oblique passage 42, the bore 45 and through the nipple l5 back into the tank l0.

After a number of cycles have been performed in the manner described, suincient air has been forced into the tank to lower the water level to a point such as that indicated by the dotted line K, atwhich the opening through the connecting nipple i5 is partially or fully uncovered. Said nipple, as previously pointed out, is located at a predetermined distance from the top of the tank l0 to maintain a proper volume of air in the tank. With the water level below K, or at any lower point such as L, air passes freely from the tank In to the chamber G through the valve assembly 43 since the ball 46 is not actuated by air as it is by water, Under this condition, no partial vacuum is produced in the chamber G, no air is drawn in through the air intake valve assembly 5! and the level of the water in the tank In is maintained until air is lost through leakage or absorption.

Thus, if the water level in the tank [6 is at or above the center line K of the nipple I5, as for instance at the point indicated by the dotted line J, a charge of air will be introduced into the tank upon each starting and stopping of the pump, while, if the level of water in the tank In is below the nipple l5, as for instance at the level indicated by the dotted line L, then no fresh charge of air will be introduced into the tank, nor will any be required.

In Figures 3 and 4 I have shown a modification of my invention in which a weight, rather than a coiled spring, is used to actuate the diaphragms. Because of the use of a weight in place of a spring, the planes of the diaphragms are changed from vertical to horizontal, in order that the weight may act through gravity. The construction and operation of the modified form of my invention will now be described.

The modified form of my device as illustrated in Figures 3 and 4 is indicated generally by the reference numeral 65. Said device is connected to the tank III by means of a nipple IS, the same as in Figures 1 and 2. The device 65 is also connected by means of a nipple 6! and piping 69 to the intake side of a pump I I.

The casing 65 is divided horizontally into two sections, a lower main section 69 and an upper section 61, the two sections being held together by screws or other fastening means (not shown) with a main diaphragm 68 clamped therebetween. A second, smaller, diaphragm 69 is secured to an annular portion '19 in the lower casing section 66, as by means of screws 1 l.

The diaphragms 68 and 69 generally are horizontal and divide the interior of the casing into upper, intermediate and lower compartments M, N and 0, respectively. The central portions of the diaphragms 68 and 69 carry a weight 12 that may suitably be in the shape of an inverted frustum of a cone, with the larger base portion 13 engaging the under surface of the diaphragm 68 and the lower smaller base portion 14 bearing against the upper surface of the lower, smaller diaphragm 69. The weight 12 is held in place by means of clamping plates 75 and 76 at the top and bottom thereof, respectively. A bolt H extends through said lower plate 16, the diaphragm 69, the weight 12, the diaphragm 68 and the upper plate 15, and is held in place by means of a nut 18. The upper end 19 of said bolt forms a stop against the under surface of the top wall of the casing part 61 limiting the upward movement of the diaphragms 68 and 69, as illustrated in Figure 4. Y

An air check valve assembly indicated generally by the reference numeral 89 is positioned in the bottom of the lower casing section 66. Said. air check valve comprises a bushing 8i threaded into a threaded bore 82 in said lower casing section 66, a passage or bore 83 extending axially through said bushing 80', a counterbored recess 94 in which is positioned a resilient valve seat 85, and a ball 86 having a stem portion 81 freely extending through said bore 83 and having an enlarged portion 88 on the lower end thereof to limit the upward movement of said stem.

The nipple I5 is threaded into a passage 96 that communicates with the chamber 0 through a reduced passage 9| and with the chamber N 6v through an oblique reduced passage 92. branch passage 93 off said passage 92 terminates in a threaded tapered bore 94 for receiving a nipple 95 carrying a pressure gauge (not shown). A check valve assembly, indicated generally by the reference numeral 96 is positioned in said smooth portion of the bore 96. Said check valve assembly 96 is provided with a threaded portion 91 threaded into a continuation 98 of said bore 90. It should be noted that the valve assembly 96 does not completely fill thebore 99 but provides a passage 99 therearound that permits flow communication into the oblique passage 92 and the chamber N.

As previously described, the check valve assembly 96 includes a ball I09 adapted to seat upon a conical seal lDl whenever water tends to flow from the tank l9 into the diaphragm mechanism 65, but that is adapted to remain unseated against a stop pin I62 when the water level in the tank is below the nipple 15.

When the pump is not operating, the weight 12 under the action of gravity holds the diaphragms 68 and 69 in their downwardly distended position as illustrated in Figure 3. When the pump ll starts up, assuming the water level to be that indicated by the dotted line J, a suction is impressed upon the chamber M of sufficient intensity to lift the weight 12 by drawing up the diaphragms 68 and 69 into their upwardly distended position, as illustrated in Figure 4. Upon this movement being initiated, the air intake valve 86 is raised to admit air into the lower chamber 0. Upon the stopping of the pump, the suction effect is released and the diaphragms 68 and 69 under the gravity action of the weight 12 drop to their downwardly distended position to expel air from the chamber 0 back through the passage 9|, the check valve assembly 96 and nipple I5 into the tank [0. The ball I09, of course, is displaced from its seat IUI as the air is expelled from the chamber 0 back into the tank Hi.

When the level of the water in the tank 10 is below the nipple 15, as indicated by the dotted line L, air is merely drawn from the tank l9 into the chamber 0 upon starting up the pump and then expelled back into the chamber [0 upon the stopping of the pump. The action is, then, similar to that already described in connection with the main form of my invention illustrated in Figures 1 and 2.

It will, of course, be understood that various details of constructions may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. In a hydro-pneumatic system including a water tank and a pump for delivering water thereto under pressure, an air volume control mechanism operating on the pressure differential between tank pressure and the pressure on the suction side of the pump comprising a casing having a first opening for connection to the water tank at about the normal water level therein and having a second opening for connection to the suction side of the pump, a pluchamber therebetween, a valve in said first opening for permitting air flow but not water flow into and out of said chamber through said first opening, an air intake from the atmosphere to said chamber, and means normally biasing said diaphragm, operative when air has been drawn into said chamber through said air intake under the suction action of the pump to thereafter move said diaphragms to force said air from said chamber back into the water tank through said first casing opening.

2. In a hydro-pneumatic system including a water tank and a pump for delivering water thereto under pressure, an air volume control mechanism operating on the pressure diiierential between tank pressure and the pressure on the suction side of the pump comprising a casing having a first opening for connection to the water tank at about the normal water level therein and having a second opening for connection to the suction side of the pump, a plurality of diaphragms within said casing for separating said first and second openings and defining a chamber therebetween, said chamber having a valve-controlled opening for permitting air flow but not water fiow into and out of said chamber through said first opening, an air intake from the atmosphere to said chamber and means biasing said diaphragms including a coiled spring acting against both of said diaphragms, said means being operative when air has been drawn into said chamber through said air intake under the suction action of the pump to thereafter move said diaphragm to force said air from said chamber back into the water tank through said first casing opening.

3. In a hydro-pneumatic system including a water tank and a pump for delivering water thereto under pressure, an air volume control mechanism operating on the pressure diiierential between tank pressure and the pressure on the suction side of the pump comprising a casing having a first opening for connection to the tank at about the normal water level therein and a second opening for connection to the suction side of the pump, flexible diaphragms of unequal effective area extending in substantial parallelism around the interior of said casing to divide the easing into a plurality of chambers including a first chamber in communication with said first opening, a second chamber communicating with said second opening, and a third chamber, a check-valve controlled intake for admitting air into said third chamber, a check valve controlled passage between said first opening and said third chamber for the flow therethrough of air in either direction but non-flow of Water from the tank to the third chamber, and means for normally urging said diaphragms in the direction opposite to that in which the suction action of the pump tends to move said diaphragms but ineffectual to do so when the pump is operating, whereby air drawn into said third chamber under the suction action of the pump is expelled from said third chamberinto the tank upon the pump being shut down.

4. In a hydro-pneumatic system including a. water tank and a pump for delivering water thereto under pressure, an air volume control mechanism operatin on the pressure diiierential between tank pressure and the pressure on the suction side of the pump comprising a casing having a first opening for connection to the tank at about the normal water level therein and a second opening for connection to the suction side of the pump, flexible diaphragms of unequal effective area extending in substantial parallelism across the interior of said casing to divide the same into a plurality of chambers including a first chamber communicating with said first opening, a second chamber communicating with said second opening, and a third chamber, a check-valve controlled intake for admitting air into said third chamber, a check-valve controlled passage between said first opening and said third chamber for the flow therethrough of air in either direction but non-flow of water from said tank to said third chamber, and means includin a coil spring acting against both of said diaphragms to urge said diaphragms in a direction opposite to that in which the suction action of the pump tends to move said diaphragms but ineffectual to do so while said pump is operating, whereby air may be drawn into said third chamber under the suction action of the pump and expelled from said third chamber into the tank upon the pump being shut down by the unequal eiTective areas of said diaphragms causing a volume decrease in said third chamber.

5. In a hydro-pnemnatic system including a water tank and a pump for deliverin water thereto under pressure, an air volume control mechanism operating on the pressure differential between tank pressure and the pressure on the suction side of the pump comprisin a casing having a first opening for connection to the tank at about the normal water level therein and a second opening for connection to the suction side of the pump, flexible diaphragms of unequal effective area extending in substantial parallelism across the interior of said casing to divide the same into a plurality of chambers including a first chamber communicating with said first opening, a second chamber communicating with said second opening, and a third chamber, a check valve control intake for admitting air into said third chamber, a check-valve controlled passage between said first opening and said third chamber for permitting the flow therethrough of air in either direction but for preventing the fiow of Water from said tank to said third chamber, and means including a gravity weight acting upon both of said diaphragms to urge said diaphragms in a direction opposite to that in which the suction action of the pump tends to move said diaphragms, but ineiiectual to do so when said pump is operating, whereby air may be drawn into said third chamber under the suction action of the pump and the unequal efiective areas of said diaphragms cause 2, volume decrease in said third chamber when said pump is shut down to expel air therefrom into said tank.

6. In a hydro-pneumatic system including a water tank and a pump for deliverin water thereto under pressure, an air volume control mechanism operatin on the pressure differential between tank pressure and the pressure of the suction side of the pump, comprising a casing having a first opening for connection to the tank at about the normal water level therein, and a second opening for connection to the suction side of the pump, two flexible diaphragms with unequal surface areas extending in substantial parallelism across the interior of the casing to divide the same into a plurality of chambers including a chamber communicating with said first opening for establishing communication with said tank, a second chamber communicatmg with said second opening, and a third chamher, an apertured member mounted between said d aphragms providing a support for one of the diaphragms and a stop for the second diaphragm,

to move said diaphragm but ineffectual to do so when said pump is operating, whereby air drawn into said third chamber under the suction action of said pump is expelled therefrom into the tank by the volume decrease in the chamber due to the unequal effective areas of said diaphragms.

7. In a hydro-pneumatic system including a water tank and a pump for delivering water thereto under pressure, an air volume control mechanism operating on the pressure difierential between tank pressure and the pressure on the suction side of the pump, comprising a casing having a first opening for connection to the tank at about the normal water level therein, and a second openin for connection to the suction side of the pump, two flexible diaphragms of unequal effective areas extending in substantial parallelism across the interior of the said casing to divide the same into a plurality of chambers including first chamber communicating with said first opening, a second chamber communicating with said second opening and a third chamber, an apertured member mounted between said diaphragms and providing a support for one diaphragm and a stop for the second diaphragm, a rigid member having a flanged cup-shaped portion centrally carried by said second diaphragm for movement into said aperture against said stop member, a check-valve controlled intake for admitting air into said third chamber, a checkvalve controlled passage between said first opening and said third chamber for the flow therethrough of air in either direction but the nonflow of water from the tank to said second chamber, and means for normally acting against the bottom of the cup-shaped portion of said rigid member to urge said diaphragms in a direction opposite to that in which the suction action of the pump tends to move said diaphragm but inefiective to do so while said pump is operating, whereby air will be drawn into said first chamber under the suction action of the pump and the unequal eflective areas of said diaphragms will cause a volume decrease in said third chamber when said pump is shut down to expel air from said chamber into the tank.

8. In a hydro-pneumatic system including a water tank and a pump for delivering water thereto under pressure, an air volume control mechanism operating on the pressure differential 10 between tank pressure and the pressure on the suction side of the pump, comprising a casing having openings for connection to the tank and to the suction side of the pump, a differential diaphragm structure within said casing including a pair of diaphragms of unequal surfaces areas separating said openings and providing a chamber therebetween of varying volume to receive a charge of air, means for admitting air into said chamber under differential action of said diaphragm structure in response to the suction of the pump when operating, means for providing for air flow but not water flow connection between said chamber and said opening for connection to the tank, and means operative when the pump shuts down for expelling said charge of air from said easing into the tank under air pressure generated by the decrease in volume of said chamber defined by said pair of diaphragms.

9. In a hydro-pneumatic system including a water tank and a pump for delivering water thereto under pressure, an air volume control mechanism operating on the pressure difierential between the tank pressure and the pressure on the suction side of the pump, comprising a casing having openings for connection to the tank and to the suction side of the pump, a difierential diaphragm structure within said casing including a pair of diaphragms of unequal efiective areas separating said connections and providing a chamber therebetween of varying volume for receiving a charge of air, means for admitting air into said chamber under difierential action of said diaphragm structure in response to the suction of said pump when operating, means for providing air fiow but not water flow connection between said chamber and said opening for connection to the tank, and means including a spring associated with said diaphragm structure and operative when the pump shuts down for expelling such charge of air from the easing into the tank under air pressure generated by the decrease in volume of said chamber defined by said pair of diaphragms.

ARTHUR W. BURKS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 135,757 Berryman Feb. 11, 1873 417,046 Kendrick Dec. 10, 1889 1,892,529 Jones Dec. 27, 1932 1,912,202 Hueber May 30, 1933 2,183,421 Brady Dec. 12, 1939 2,220,209 Carpenter Nov; 5, 1940 2,435,053 Piccardo Jan. 27, 1948 FOREIGN PATENTS Number Country Date 36,505 Germany 1886 

